• KSCE Journal of Civil and Environmental Engineering Research
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• v.36 no.1
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• pp.105-114
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• 2016

With approximately 20 million transportation card data entries of the metropolitan districts being generated per day, application of the data to management and policy interventions is becoming an issue of interest. The research herein attempts a model of the possibility of dynamic demand change predictions and its purpose is thereby to construct a Dynamic Passengers Trip Assignment Model. The model and algorithm created are targeted at city rail lines operated by seven different transport facilities with the exclusion of travel by bus, as passenger movements by this mode can be minutely disaggregated through card tagging. The model created has been constructed in continuous time as is fitting to the big data characteristic of transport card data, while passenger path choice behavior is effectively represented using a perception parameter as a function of increasing number of transfers. Running the model on 800 pairs of metropolitan city rail data has proven its capability in determining dynamic demand at any moment in time, in line with the typical advantages expected of a continuous time-based model. Comparison against data measured by the eye of existing rail operating facilities to assess changes in congestion intensity shows that the model closely approximates the values and trends of the existing data with high levels of confidence. Future research efforts should be directed toward continued examination into construction of an integrated bus-city rail system model.

• 한국해양학회지
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• v.27 no.1
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• pp.78-90
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• 1992

The present study is aimed to investigate the relationship between the distribution of benthic macro fauna and environments in the Mangyung-dongjin tidal flat developed on the west coast of central korea. Samples were taken from 69 sites established on 8 transect lines running perpendicular to the coast. The 69 sites located in the range of -250 to 230 cm height from the mean sea level were categorized into 4 levels of exposure duration. The mean grain sizes of the surface sediments varied from 1.5 to $7.9{\varphi}$. Silty sands and sands were dominant sediment facies on the tidal flat. A total of 64 species of invertebrates was collected and the mean density was $1,335{\;}indiv{\cdot}\textrm{m}^2$. The dominant species was Laternula cf. limicola of Bivalvia (71% of total counts), followed by Umbonium thomasi of Gastropoda (22%), and Lingula anatina of Brachiopoda (2.6%). These 3 species comprised 95.5% of total individual number. The distribution of benthic animals was closely related with the duration of tidal exposure. Perinereis association was the characteristic for the most exposed area, and followed by Macrophthalmus and Bullacta-Mactra-Umbonium association along the degree of exposure duration.

• The Journal of the Korea Contents Association
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• v.13 no.3
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• pp.435-443
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• 2013

While rural highways carry on lower traffic volumes, the deviations of running speeds between vehicles appear to be higher on rural highways than urban highways. The speed characteristic of rural highways is adding to pedestrian-related accidents which occur on a crosswalk with poor sight distance due to the limits of car headlights and lighting. Specially, the aged was mostly occupied in nighttime-related accidents on crosswalks, and pedestrians crossing on the far side of approaching vehicles appear to have the probability of fatality higher than the near side. An alternative is needed to resolve the compounded accidents, and then this study is to establish a new approach to an optimum lighting environment on a crosswalk to improve pedestrian safety. This study was conducted by a survey and a field study on the lighting of existing crosswalks. The field study shows that the existing lighting has the problem of wasting energy and impeding walking due to glare. The survey shows that nighttime sight distance on a crosswalk is required to improve and that road users prefer to be brighter pedestrian waiting space together with the crosswalk. Thus, a lighting environment that is not too bright and illuminates the crosswalk and the pedestrian waiting space is needed to implement.

• The Journal of the Korea Contents Association
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• v.13 no.3
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• pp.392-401
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• 2013

This study was conducted to research the Selection Attribute for Pension which is located in the region of S. Gyeonggi-do. We intended to find the best choice point for reserving the pension using IPA and suggest or provide strategic implications and marketing method for running the pension. The survey was conducted from the early January to the end of March in 2012 with one to one method. A total of 300 questionnaires were distributed and 229 responded questionnaires were reliable to be used as a sample. The result of the survey was analyzed by using SPSS 15.0 version for window with Paired t-test and IPA method. Frequency Analysis was also conducted for the characteristic of samples. Findings are presented and discussed in three areas. First, the cleanliness of rooms, service for customer, heating and cooling system are the key important factors for the choice of pensions. Secondly, all factors are statistically significant level(p<0.01, p<0.001) as a results of performing IPA method. Thirdly, the result has shown that the varity of programs in the pension have significant impact on the customers' choice and satisfaction.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.41 no.1
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• pp.23-34
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• 2004

This paper presents architecture and control method of packet scheduler to guarantee QoS of high quality streaming services in high-speed packet-switched networks. Since streaming services need far more stringent QoS requirements than the typical sort of burst data applications, they should be guaranteed minimum bandwidth and end-to-end delay bound to each flow, regardless of the behavior of other flows. To meet these requirements, a packet scheduler isolate a flow from the undesirable effects of other flows and provides end-to-end delay guarantees for individual flow and divides stringently the available link bandwidth among flows sharing the link. Until now, many vendors are developing traffic management chips running at 10Gbps, but most of chips have drawbacks to support high quality streaming services. In this paper, we investigate the drawbacks of commercial TM chips and traffic characteristic of streaming services and present implementation frameworks of the proposed packet scheduler. Finally, we analyze the simulation results of the proposed scheduler.

• Journal of Elementary Mathematics Education in Korea
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• v.5 no.1
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• pp.37-53
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• 2001

This paper tries to find out about organizational and managemental aspect of Korean curriculum through a comparison between Korea's 7th elementary mathematics curriculum and that of Japan's elementary mathematics curriculum, which will start in m2 through researching various literatures. The main characteristic of this elementary mathematics curriculum is that Korea has organized a teaming program that tended to individual differences, and focused on student-centered activities and communication based on constructivism. On the other hand, Japan reduced learning contents a lot by running 5-schooldays a week so that 80% of teaching time can be spent to help the students master mathematical contents of the textbook. This leaves 20％ of teaching time to be used for improving mathematical thinking power as a foundation of creativity through mathematical activities. Korea's teaching time spent for elementary mathematics is about 80％ of Japan's, which is also less than that of other country's. Less time in teaming mathematics will lead to decrease in teaming ability. Therefore, there is a need for increased teaching time in mathematics. Korea's revision of curriculum is about 5 years which is often compared to that of Japan's 10 years. Frequent revising is good in that it reflects the social demand, but it can cause much confusion and problems in accepting and applying its program in a real classroom setting, which is why it needs to be looked at again. The direction, objective and assesment of revision fits the demands of international trends and essentials of mathematics. Japan puts its emphasis on learning through repetition and Korea puts its emphasis on problem solving and communication. Regarding assesment, both Korea and Japan is looking for ways to find various assessing ways which will focus on mathematical process rather than the mathematical results, and also will put emphasis on criterion-directed assesment to measure goal achievements. However Japan emphasize on using report cards of assesment to help mathematics learning.

• Korean Journal of Poultry Science
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• v.46 no.4
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• pp.223-234
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• 2019

This study investigated the effects of thawing methods and storage time on the quality of frozen duck meat. Meat was obtained from eight-week-old Korean native ducks (average weight=2.8 kg). Seventy-two samples were divided into eight treatments (three replicates/treatment, three samples/replicate) with 2 × 4 factorial arrangement based on two thawing methods (under running water at 12℃ for 3 h and in a refrigerator at 5℃ for 24 h) and four storage times (1, 3, 6, and 12 months). CIE b^* was significantly different among different storage time treatments, reaching its lowest after 6 months (P<0.05). Cooking loss did not differ between storage times; however, it was significantly lower following application of the fast thawing treatment (P<0.05). Water-holding capacity of meat stored for one month was highest compared to that of meat stored for a longer period (P<0.05). Additionally, there were significant differences based on storage time in γ-linoleic acid (C18:3n6) and eicosenoic acid (C20:1n9) contents (P<0.01), as well as in protein contents (P<0.05). Palmitoleic acid (C16:1n7) typically decreased after three months of storage; however, this decline was not significant compared to other storage times. Essential amino acids contents, except methionine, were significantly difference at six and 12 months of storage (P<0.05). Similarly, non-essential amino acid contents, except tyrosine, were significantly different among storage periods (P<0.05, P<0.01). Alternatively, there were no significant differences in the chemical composition, fatty acid content, or amino acid content based on the thawing method.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.42 no.5
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• pp.1009-1019
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• 2017

Mobile Edge Computing(MEC) is a emerging technology to cope with mobile traffic explosion and to provide a variety of services having specific requirements by means of running some functions at mobile edge nodes directly. For instance, caching function can be executed in order to offload mobile traffics, and safety services using real time video analytics can be delivered to users. So far, a myriad of methods and architectures for personalized service recommendation have been proposed, but there is no study on the subject which takes unique characteristics of mobile edge computing into account. To provide personalized services, acquiring users' context is of great significance. If the conventional personalized service model, which is server-side oriented, is applied to the mobile edge computing scheme, it may cause context isolation and privacy issues more severely. There are some advantages at mobile edge node with respect to context acquisition. Another notable characteristic at MEC scheme is that interaction between users and applications is very dynamic due to temporal relation. This paper proposes the local service recommendation platform architecture which encompasses these characteristics, and also discusses the personalized service recommendation mechanism to be able to mitigate context isolation problem and privacy issues.

• Applied Microscopy
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• v.42 no.1
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• pp.17-26
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• 2012

Histologic and microstructural changes during the postembryonic development of the wolf spider Arctosa kwangreungensis were studied using light and scanning electron microscopy to examine the relationship between a morphological differentiation and behavioral properties. The postembryo with abdominal yolk sac was stayed inactive in the egg case because its muscular and visual systems were not fully developed to a functional level. The first instar spiderlings, developed from the postembryo by a first molting process, started to exhibit its pigmentation on their body cuticles. In particular, undifferentiated cell clusters of central nervous system (CNS) were densely distributed within the cephalothorax, and highly differentiated abdominal ganglion was observed. They had a characteristic visual system looks more like its adult counterpart, and had segmented appendages looks more like the tiny spiders containing well oriented muscular system. After 3rd instar, spiderlings grew more rapidly with accordance to their consistent growth and periodical molting processes. Thus, the relative area of CNS with respect to cephalothorax was gradually decreased, instead a pair of venom glands, musculature, and connectives occupied the residual area. It has been revealed that the early development of spider can be controled by the feeding condition of larval period, since histologic and microstructural differentiations in both appendages and optic system were completed at the second instar. In particular, behavioral properties of the wandering spiders that depend on vision and their running ability were deeply related to physiological differentiation of the microstructural development.

• Journal of Veterinary Clinics
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• v.26 no.6
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• pp.595-599
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• 2009

Sarcocystis grueneri-like sarcocysts were found from the cardiac muscles of a rearing red deer (Cervus elaphus) carcass in Korea. In the light microscopical examination of sarcocysts, they were oval to spherical cysts and 90-170$\times$110-380 ${\mu}m$ in size. However, there was no inflammation and myofiber degeneration. In the transmission electron microscope, these cysts were located within the sarcoplasm of the host cell and filled with merozoites. The sarcocysts were enclosed by a very thin wall (0.45-0.6 ${\mu}m$ thick) that consists of protrusions and ground substance. The primary cyst wall formed numerous strip-like protrusions which were 0.2-0.3 ${\mu}m$ wide and up to 4.2 ${\mu}m$ long. The protrusions were running in parallel with the surface of the cyst. A characteristic of the cyst wall was absent of fibrils inside the protrusions. Merozoites in the compartment measured about $15\times4\;{\mu}m$. The merozoite consisted of four regions: micronemes and rhoptries, amylopectin granule, nucleus, and amylopectin granules. The number of rhoptry was counted in 7-13.